In this compelling, readable book, Lewis (Thread of Life, etc.) inquires into the controversies and ""paradigm shifts'' that have marked the views of evolutionists Darwin, Alfred Russel Wallace, T. H. Huxley and others in the era that witnessed the discovery of the bones of Neanderthal Man (1856); as well as such modern-day theorists and field-workers as the Leakeys (Louis, Richard and Mary) and Donald Johanson, who found the bones of ``Lucy.'' Covering the history of the hunt for fossil evidence supporting Darwin's argument for man's ``descent,'' he shows through superb research and lively interviews how profoundly subjective the views of scientists have been whenever they have tried to determine when, how and why humans (``hominids'') branched off from apes. Here are descriptions of African fossil-digs, arguments about the naming of fossil finds, ego-clashes between the likes of Richard Leakey and Donald Johansonnone of it destroying evolutionary theory itself, but all of it, with insight and submerged humor, showing how all-too-human science can be. Photos. Macmillan Book Club alternate. (September 17)